Masonry units are made of various suitable materials, such as, for example, concrete, to form generally rectangular shaped blocks that can be stacked on top of one another to act as a building material for various load-bearing structures. Concrete masonry units are usually reinforced with rebar to provide the structure greater resistance to lateral forces. Concrete masonry units, however, rely heavily on mortar joints to join individual units to one another. Accordingly, it is desired to have masonry units or concrete blocks that are capable of forming a structure with enhanced strength and stability compared to that provided by concrete masonry units in the prior art.